Automatic feed control mechanism



Jan. 16, 1962 'R. K. MILLER AUTOMATIC FEED CONTROL MECHANISM 4Sheets-Sheet 1 Filed Dec. 6, 1960 Jan. 16, 1962 R. K. MILLER AUTOMATICFEED CONTROL MECHANISM 4 Sheets-Sheet 2 Filed Dec. 6, 1960 Jan. 16, 1962R. K. MILLER 3,017,060

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LVE'N'T'UI? 7 TUFAEH York Filed Dec. 6, 1969, Ser. No. 74,036 8 Claims.(Cl. 226-10) This invention relates to feed control mechanisms andparticularly to a feed control mechanism utilized f feeding an elongatedelement, such as wire, strand, rod strip, etc., having variedcross-sectional area portions.

There are many applications in industry where it is necessary to handleelongated elements having varied cross-sectional area portions and toadvance them to certain tooling stations. For example, in thefabrication of wire filaments for electron tubes, a continuousmolybdenum wire prewound with successive enlarged coil portions, twocoil portions being separated by a reduced skip or long straightportion, is fed intermittently to stations for cutting and forming thewire to a desired filament configuration. Heretofore, the wire feed wasmanually controlled by an operator who stopped the feed each time asmall skip portion, located between the coils of a pair, was positionedin a fixed relationship to the forming tool. It was necessary for theoperator to utilize a microscopic lens for positioning the wire due toits very small size, for example, the wire having a .006- inch diameterand the enlarged coil portion having an .OOS-inch diameter. This notonly required a skillful operator for accurately controlling the wirefeed but also resulted in the consumption of much time and eye fatigueto the operator.

The object of this invention is a mechanism for automaticallycontrolling the intermittent feed of an elongated element having asuccession of varied cross-sectional area portions.

According to the general features of the invention, the wire or otherelement is passed through a chamber containing pressurized fluid, thevaried cross-sectional area portions of the wire controlling the fluidpressure Within the chamber for energizing a circuit to control thefeeding means.

In one embodiment, a filament wire feeding mecha' nism is controlled byan air gage switching device in accordance with the location of theenlarged coil and reduced skip portions of the wire as the wire passesthrough an air pressure chamber. Upon a passing of the enlarged coilportions through the entrance and exit orifices of the chamber, the airpressure within the chamber increases to energize a circuit to maintainmovement of the wire feeding means. As the reduced skip portions passthrough the entrance and exit orifices, air escapes from the chamberthrough the orifices causing a pressure decrease within the chamber anda de-energizing of the circuit to stop the wire feed. Conversely, ifdesired, the pressure decrease caused by the passing of the reduced skipportions through the orifices can be utilized to energize the wirefeeding means circuit and the pressure increase can be utilized tode-energize said circuit.

Other objects and a fuller understanding of the invention may be had byreferring to the following description and claims taken in conjunctionwith the accompanying drawings in which:

nite States Patent FIG. 1 is a plan view of an apparatus embodying thefeed control mechanism;

FIG. 2 is a front elevational view of an apparatus embodying the feedcontrol mechanism;

FIG. 3 is a view taken along lines 33 of FIG. 1;

FIG. 4 is a fragmentary view of cutting and forming units utilized forforming a wire filament; and

FIG. 5 is a schematic wiring diagram for controlling the wire feedingmeans.

With respect to the drawing, the invention is incorporated in an airpressure sensing unit 10 for automatically controlling the feed to wire11 to a cutting tool 12 and forming tool 13 of a machine 14. The wirehas a suc cession of prewound pairs 16 of enlarged coiled portions, eachpair 16 including two coil windings 17-17 which are separated by areduced small skip 18 and each pair 16 being separated by a reducedlarge skip 19 in the winding. The wire 11 is fed from a reel 15 by apair of drive feed rollers 20, hereinafter described in more detail,through the air pressure sensing unit 10 to the cutting and formingstations 12 and 13, respectively.

Regarding the pressure sensing unit 10, the diameters of the entranceorifice 25 and exit orifice 26 are slightly larger than the winding ofeach enlarged coil pair 16 passing therethrough. The distance in thepressure chamber 27 between the entrance and exit orifices 25 and 26preferably is slightly larger than one coiled pair 16 so that when asingle pair is located within the chamber,

the large skip portions 19 of the wire are located in the entrance andexit orifices 25 and 26, respectively. However, it is noted that thedistance between the orifices 25 and 26 can be such to accommodate anymultiple of the lengths of the different diameter portions of wire.Further, the length of each different diameter portion of Wire can bealternately varied, if desired.

Compressed air is admitted from a source (not shown) through acornmerical air gaging unit or controller 30 and through tube 31 leadinginto the chamber 27. It is noted that the invention is not limited tothe use of compressed air as the fluid supplied under pressure to thechamber may be in either a gaseous or liquid state. However, it ispointed out that compressed air, which is generally convenientlyobtainable, is best suited for this purpose.

As seen in FIG. 5, upon the actuation of power switch 32, current passesthrough resistor 33 and pilot light 34 is illuminated to indicate thatpower is on. Power is supplied to a converter 35 which converts V. AC.to 28 V. DC for operation of an electric clutch-brake unit 36. Poweralso is supplied to the air controller unit 30 and to the rest of thecircuit.

At the commencement of a cycle (as seen in FIG. 3), a coiled pair 16 islocated within the chamber 27 so that the large skip portions 19 arelocated in the entrance and exit orifices 2526, respectively. Air valve40 is opened to admit air through the controller unit 30 and into thechamber 27. A switch 45, as seen in FIG. 5, is turned to the on positionenergizing motor relay 47. The motor switch contacts 48 are closedthrough motor relay 47 for starting motor 49 which drives a cam shaft50. A cam 51 connected to the shaft 50, strikes and momentarily closes amicroswitch 52 upon each complete revolution. When switch 52 is closed,the clutch of the clutch-brake unit 36 is engaged through relay 42 andthe closing of contacts 43 to drive the feed rollers to feed the wire.

From the time switch 52 is closed and the wire is being fed throughsensing unit 10, the air pressure within the sensing chamber 27 buildsup as the entrance and exit orifices and '26 become substantiallyblocked due to the coil winding 17 of one pair passing through the exitorifice 26 and the coil winding 17' of a succeeding pair passing throughthe entrance orifice 25. When cam 51 rotates out of contact from andopens microswitch 52, the feed continues due to the pressure build-upwithin the chamber 27 causing pressure-sensitive switch 41 to close tomaintain current through the clutch-brake relay 42 for keeping theclutch in the engaged positions.

When a coiled pair is completely located within the chamber so that thelarge skip winding portions 19 are disposed in the entrance and exitorifices 25 and 26, the air within the chamber is permitted to escapethrough the now unblocked entrance and exit orifices. This causes theair pressure within the chamber to be reduced to a low value. Upon thereduction of the air pressure in chamber 27, pressure-sensitive switch41 opens to de-energize relay 42 to release the clutch and activate thebrake to stop the feeding of the wire. In other words, as the unwoundportions or large skips in the winding pass through the pressure chamber27, more air escapes and thereby reduces the air pressure within thechamber which causes an electric impulse to be produced to disengage theclutch and stop the wire feed.

During the feeding of the wire, cutter cam 56 and forming tool cam 57,connected to the continually rotating shaft 50, are sequentiallyoperated. As seen in FIG. 4, cutting tool 12 cuts the wire at the largeskip portions 19 and the forming tool 13 passes between forming rollers60 to engage the small skip portion 18 to form a substantially V-shapedfilament. After the cutting and forming operations, cam 51 contactsmicroswitch 52 which closes to energize the clutch-brake relay 42 whichcauses the brake to release and the clutch to engage and feed the wire.The mechanism is now ready to commence a new cycle.

It is to be understood that the above-described arrangements are simplyillustrative of the application of the principles of the invention.Numerous other arrangements may be readily devised by those skilled inthe art which will embody the principles of the invention and fallwithin the spirit and scope thereof.

What is claimed is:

1. A feed control for an elongate element having a succession ofportions each consisting of a length of relatively large cross-sectionalarea and a length of relatively small cross-sectional area, whichcomprises, a chamber in the path of the element having entrance and exitorifices spaced apart by a multiple of the length of the elementportions, means for admitting fluid under pressure to the chamber, meansfor advancing the element through the chamber, and means responsive to achange of pressure in the chamber as the element passes therethrough forcontrolling the feed of the element.

2. A feed control for an elongate element having a succession ofportions each consisting of a length of relatively large cross-sectionalarea and a length of relatively small cross-sectional area, whichcomprises, a chamber in the path of the element having entrance and exitorifices spaced apart by a multiple of the length of the elementportions, the orifices being slightly larger than the cross-sectionalareas, means for admitting fluid under pressure to the chamber, meansfor advancing the element through the chamber, means for activating theadvancing means periodically, and means responsive to .a change ofpressure in the chamber as the element passes therethrough forcontrolling the feed of the ele- 'ment.

3. A feed control for an elongate element having a succession ofportions each consisting of a length of relatively large cross-sectionalarea and a length of relatively small cross-sectional area, whichcomprises, a chamber in the path of the element having entrance and exitorifices spaced apart by a multiple of the length of the elementportions, the orifices being slightly larger than the cross-sectionalareas, means for admitting fluid under pressure to the chamber, meansfor advancing the element through the chamber, means for activating theadvancing means periodically, and switching means cooperating wi-th theactivating means in response to a change of pressure in the chamber asthe element passes therethrough for controlling the feed of the element.

4. An automatic control for the intermittent feed of an elongatedelement having a succession of substantially identical portions eachconsisting of a length of relatively large cross-sectional area and alength of relatively small cross-sectional area, which comprises, achamber in the path of the element having element entrance and exitorifices, the diameter of the orifices being slightly larger than thecross-sectional areas, means for admitting fluid under pressure to thechamber, means for moving the element through the chamber, means formomentarily activating the moving means periodically, and switchingmeans cooperating with the activating means for maintaining movement ofthe moving means upon a fluid pressure increase within the chamber asthe large cross-sectional areas pass through at least one orifice, andfor stopping the moving means upon a fluid pressure decrease as thesmall cross-sectional areas pass through said orifice.

5. A feed control according to claim 4 in which the switching meanscomprises a fluid gaging unit through which the fluid passe to thechamber, and a pressuresensitive switch within the unit operated by afluid pressure increase within the chamber as the large crosssectionalareas pass through the chamber orifice to maintain the element feed.

6. A feed control according to claim 4 in which the activating meanscomprises a shaft, means for driving the shaft, a switch for controllingthe moving means, and a cam on the shaft for operating the switch.

7. An automatic control mechanism for the intermittent feed of anelongated element having successive first and second diameter portions,the first diameter portion being larger than the second diameterportion, which comprises, a chamber in the path of the element havingentrance and exit orifices, the diameter of the orifices being slightlylarger than the first diameter portions, means for admitting fluid underpressure to the chamber, means for moving the element through thechamber, a first switch for controlling the moving means, a shaft, meansfor driving the shaft, a cam on the shaft to momentarily operate thefirst switch for driving the moving means to feed the element, a fluidgaging unit through which the fluid passes to the chamber, apressure-sensitive switch within the unit, the pressure-sensitive switch,being operative to maintain movement of the moving means under a fluidpressure increase within the chamber as the first diameter portions passthrough the chamber orifices, and being inoperative upon a fluidpressure de crease as the second diameter portions pass through saidorifices.

8. An automatic control for the intermittent feed of an elongatedelement having a plurality of successively prewound enlarged coilportions, each portion being separated by a reduced skip in the winding,which comprises, a chamber in the path of the element having axiallyaligned entrance and exit ends, the diameter of the ends being slightlylarger than the enlarged coil portions, means for admitting air underpressure to the chamber, an air gaging unit through which the air passesto the chamber, a pressure-sensitive switch within the unit having feedand non-feed positions, the switch being normally open in the non-feedposition, means for moving the element through the chamber, a normallyopen second switch for controlling the moving means, a common relayenergized through the pressure-sensitive and second switches forcontrolling the moving means, a shaft, means for driving the shaft, acam on the shaft to momentarily close the second switch to energize therelay to actuate the'moving means to feed the element, the second switchopening and the pressure-sensitive switch closing to the feed positionand to maintain movement of the moving means upon an air pressureincrease within the chamber as the enlarged coil portions pass throughthe chamber ends to substantially block the air within the chamber fromescaping, and the pressure-sensitive switch opening to stop the movingmeans upon a fluid pressure decrease Within the chamber as the reducedskip portions pass through the chamber ends to permit the air to escapefrom the chamber.

References Cited in the file of this patent UNITED STATES PATENTS Milleret a1. Aug. 28, 1956 2,909,275 Hitchcock Oct. 20, 1959

